topic Re: How to Configure LPC55S28 I2C to Fast Mode Plus in LPC Microcontrollers

How to Configure LPC55S28 I2C to Fast Mode Plus

AmberLin — Fri, 27 Oct 2023 09:48:31 GMT

Hi Community,

I need 1Mbits/s I2c communication, but it just reach 800kbits/s

The attachment lpcxpresso55s28_i2c_interrupt_b2b_transfer_master.7z is SDK example code that use FC4 (PIO1_20 and PIO1_21).

In addition, I refer to How to Configure LPC55S16 I2C to Fast Mode Plus

It seems to be a different problem, because it already enable the FRG4 in example code.

The attachment LPC55S28_test.7z is my own code that use FC1 (PIO0_13 and PIO0_14) based on MCUXpresso config tool.

I follow the document UM11126 (Table 336.) to set pins with config tool, but the result is still 800k.

Re: How to Configure LPC55S28 I2C to Fast Mode Plus

RaRo — Tue, 31 Oct 2023 15:10:26 GMT

Hello @AmberLin,

Could you please tell us if you are using an NXP's EVK or a custom board? Which slave are you connecting with the master LPC5528?

Also, could you please check the I2C-bus specification and user manual and LPC55S2x/LPC552x Product data sheet. Section 11.9 I2C-bus? There is mentioned some extra considerations of bus timing.

Kind regards, Raul.

Re: How to Configure LPC55S28 I2C to Fast Mode Plus

AmberLin — Wed, 01 Nov 2023 02:19:05 GMT

Hi @RaRo

I'm using LPC55S28-EVK, and the slave that I am connecting with is HX83192 automotive TDDI.

I'll check documents you provide.

By the way. Refer to the document UM11126 CH.33.

Are FC0 to FC7 able to reach 1M, or just FC1 (PIO0_13 and PIO0_14) can be configured to 1M?

It doesn't mention about which are the specific I2C pins for FM+.

Best Regards.

Amber Lin.

Re: How to Configure LPC55S28 I2C to Fast Mode Plus

RaRo — Wed, 01 Nov 2023 16:29:27 GMT

Hello @AmberLin,

Could you please try using the i2c_polling_transfer_master and/or i2c_dma_transfer_master examples? With those have you achieved a faster speed communication?

Are FC0 to FC7 able to reach 1M, or just FC1 (PIO0_13 and PIO0_14) can be configured to 1M?

Let us double check this information, since as you mentioned it is not very clear which specific I2C pins should be used for Fast-mode Plus or High-speed mode. We will let you know any information regarding your case as soon as possible.

Best regards, Raul.